Summary Statistics on Plant Observations from the CMF and ASM Sample
| Mean | SD | |
|---|---|---|
| Total value of shipment ($m) | 97.92 | 445.90 |
| Total wages ($m) | 10.95 | 35.78 |
| Total employees | 299.80 | 732.50 |
| Total labor hours (000) | 717.10 | 6465.00 |
| HHI (SIC3–county–year) | 0.520 | 0.347 |
| HHI (SIC4–county–year) | 0.651 | 0.338 |
| HHI (SIC3–CZ–year) | 0.338 | 0.308 |
| HHI (SIC4–CZ–year) | 0.481 | 0.343 |
| HHI (SIC3–county–year) = 1 | 0.211 | 0.408 |
| HHI (SIC3–CZ–year) = 1 | 0.080 | 0.271 |
| Log labor productivity | 4.49 | 0.86 |
| Average wage ($000) | 41.54 | 14.18 |
| Average wage ($000), production | 36.82 | 13.65 |
| log(employment, SIC3–county–year) | 6.24 | 1.61 |
| log(employment, SIC4–county–year) | 5.75 | 1.56 |
| log(employment, SIC3–CZ–year) | 7.10 | 1.63 |
| log(employment, SIC4–CZ–year) | 6.40 | 1.60 |
| Plants per segments (SIC3) | 15.17 | 34.08 |
| Plants per firm | 50.88 | 72.68 |
| Plant age | 16.49 | 10.80 |
| Unionization rate | 0.198 | 0.123 |
| Observations (plant–years) | 946,000 |
Notes: This table presents descriptive statistics on the manufacturing plant–year observations used in the analysis from the CMF and ASM databases for the period 1978–2016. We require each observation in the sample to have all variables necessary to compute average wages, labor productivity, and value added per worker (and their lagged values). Total value of shipments is TVS in the CMF and ASM databases and a measure of sales from plants in million dollars. Total wage is the sum of wages for production and nonproduction workers in million dollars. Total employees is the number of total employees. Total labor hours is the production worker equivalent human hours in thousands. HHI (SIC3 or 4–employment by firms at the industrycounty or CZ–year) is the Herfindahl–Hirschman Index (HHI) of employment by firms at the county or commuting zone (CZ)–industry (three- or four-digit)–year level. HHI (SIC3–county or CZ–year) = 1 is an indicator variable equal to one if HHI = 1, and zero otherwise. HHI (SIC3 or 4–year) is the Herfindahl–Hirschman Index (HHI) of employment by firms at the industry (three- or four-digit)-year level. log(employment, SIC3 or 4–county or CZ–year) is the log number of employees at the county or CZ–industry (three- or four-digit)–year level. Labor productivity is defined as output divided by total labor hours (a quantity-based measure of labor productivity). Average wage is computed as total wage divided by total employees (in thousand dollars). Average wage, production is computed as production employee wage divided by total production employees (in thousand dollars). log(employment, SIC3 or 4–county or CZ–year) is the log number of employment at the county or CZ–industry (three- or four-digit)–year level. Plants per segment is the number of plants in a given three-digit SIC industry segment of a given firm. Plants per firm is the total number of plants of a given firm. Plant age is the number of years since a plant’s birth, which is proxied either by the flag for plant birth in the Longitudinal Business Database (LBD) or by its first appearance in the CMF or ASM database, whichever is earliest. Unionization rate is the industry-level percentage of the workforce covered by collective bargaining collected from the CPS. The number of observations is rounded to the nearest thousand to follow the U.S. Census Bureau’s disclosure rules.